Abstract: Objective The aim of this study was to investigate diagnostic performance of contrast-enhanced ultrasonography(CEUS) and enhanced CT (CECT)/magnetic resonance imaging (MRI) liver image reporting and data system (LI-RADS) in the diagnosis of patients with small hepatocellular carcinoma (sHCC). Methods A total of 102 patients with intrahepatic space-occupying lesions (SOL) were encountered in our hospital between January 2019 and December 2023, and the patients enrolled all had SOL less than 1 cm. All patients underwent CEUS and CECT /MRI check-up, intrahepatic SOL were assorted based on LI-RADS, and diagnosis was determined by histo-pathological examination. Results Of 102 SOL, CEUS judged as LR3, LR4, LR5 and LRM in 11, 13, 67 and 11 cases, significantly different as compared to 18,20, 61 and 3 cases by CECT/MRI did(P=0.033); final diagnosis was made by pathological examination and showed sHCC in 92 cases and mixed liver cancer in 2 cases, and benign lesions in 8 cases, including cirrhotic nodules in 4 cases and focal proliferative nodule (FPN) in 4 cases; sensitivity, specificity and accuracy by CEUS were 62.5%, 98.9% and 96.1%, all not significantly different compared to 75.0%,97.9% and 96.1% by CECT/MRI (P＞0.05). Conclusion CECT/MRI and CEUS could help clinicians make an appropriate diagnosis early in patients with intrahepatic small SOL, and we recommend the LI-RADS for relatively correct diagnosis. For patients with intrahepatic SOL, the histo-pathological examination is never too important in clinical practice.

Key words: Hepatocellular carcinoma, Contrast-enhanced ultrasonography, Contrast- enhanced CT, Magnetic resonance imaging, Liver imaging reporting and data system, Diagnosis